YAML Diff Viewer Free Online Tool 2026

Last updated March 22, 2026

YAML Diff Viewer Examples

The YAML Diff Viewer compares two YAML documents structurally, highlighting added, removed, and modified keys at every level. Below are practical examples showing how the diff works across common configuration scenarios.

Basic Key Comparison

Document A (original):

app:
  name: my-service
  version: "1.0.0"
  port: 8080
  debug: false

Document B (updated):

app:
  name: my-service
  version: "1.1.0"
  port: 9090
  debug: true
  timeout: 30

Diff result:

• app.version: "1.0.0" → "1.1.0" (modified, shown in yellow)
• app.port: 8080 → 9090 (modified, shown in yellow)
• app.debug: false → true (modified, shown in yellow)
• app.timeout: (added in B, shown in green)

Kubernetes Manifest Comparison

Comparing a Deployment manifest between staging and production:

Staging:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: web-app
  namespace: staging
spec:
  replicas: 1
  template:
    spec:
      containers:
        - name: web
          image: myapp:1.2.0
          resources:
            requests:
              memory: "128Mi"
              cpu: "250m"

Production:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: web-app
  namespace: production
spec:
  replicas: 3
  template:
    spec:
      containers:
        - name: web
          image: myapp:1.3.0
          resources:
            requests:
              memory: "256Mi"
              cpu: "500m"

Diff highlights:

• metadata.namespace: staging → production
• spec.replicas: 1 → 3
• containers[0].image: myapp:1.2.0 → myapp:1.3.0
• resources.requests.memory: 128Mi → 256Mi
• resources.requests.cpu: 250m → 500m

Docker Compose Comparison

Original compose file:

version: "3.8"
services:
  db:
    image: postgres:14
    environment:
      POSTGRES_DB: appdb
      POSTGRES_USER: admin
    ports:
      - "5432:5432"

Updated compose file:

version: "3.8"
services:
  db:
    image: postgres:15
    environment:
      POSTGRES_DB: appdb
      POSTGRES_USER: admin
      POSTGRES_PASSWORD: secret
    ports:
      - "5432:5432"
    volumes:
      - db_data:/var/lib/postgresql/data
volumes:
  db_data:

Diff result:

• services.db.image: postgres:14 → postgres:15 (modified)
• services.db.environment.POSTGRES_PASSWORD: (added)
• services.db.volumes: (added)
• volumes: (added top-level key)

CI/CD Pipeline Comparison

Comparing GitHub Actions workflow files:

Before:

on:
  push:
    branches: [main]
jobs:
  build:
    runs-on: ubuntu-20.04
    steps:
      - uses: actions/checkout@v2
      - run: npm install
      - run: npm test

After:

on:
  push:
    branches: [main, develop]
jobs:
  build:
    runs-on: ubuntu-22.04
    steps:
      - uses: actions/checkout@v3
      - run: npm ci
      - run: npm test
      - run: npm run build

Diff highlights:

• on.push.branches: [main] → [main, develop] (sequence item added)
• jobs.build.runs-on: ubuntu-20.04 → ubuntu-22.04
• steps[0]: actions/checkout@v2 → actions/checkout@v3
• steps[1]: npm install → npm ci
• steps[3]: npm run build (added)

Semantic vs Text Diff

These two YAML documents are semantically identical but formatted differently. A text diff would show many changes; the structural diff shows zero differences:

# Document A
server: {host: localhost, port: 3000}

# Document B
server:
  host: localhost
  port: 3000

Structural diff result: No differences found.

Anchor and Alias Handling

The viewer resolves anchors before comparing:

# Document A
defaults: &defaults
  retries: 3
  timeout: 10
service:
  <<: *defaults
  name: api

# Document B
service:
  retries: 3
  timeout: 10
  name: api

Structural diff result: No differences found (anchors resolved to same values).

Common Use Cases

• Reviewing infrastructure-as-code pull requests before merging
• Comparing Kubernetes manifests across dev, staging, and production
• Auditing configuration drift between environments
• Understanding what changed between two versions of a Helm chart
• Validating that a deployment only changed the intended fields
• Documenting intentional differences between environment configs
• Debugging environment-specific issues by isolating config differences

The YAML Diff Viewer focuses on semantic meaning rather than raw text, so reformatting or reordering keys never creates false positives. Only real value changes appear in the diff output.